Destructor milling mechanism

ABSTRACT

An improved destructor mechanism is described for reducing documents, paper and similar fibrous materials to a fluffy illegible consistency. The mill to be described is equipped with a hood at the entrance to the mill, into which material which is not accepted initially by the mechanism is discharged back through the entrance and circulated, to be reintroduced through the entrance into the mechanism until it is accepted and reduced to the aforesaid fluffy consistency. The mill to be described is particularly advantageous, in that bulky material can be fed into it without the tendency for the apparatus to become jammed, and no special care need be taken in the manner in which the material is fed into the mechanism, or of the size or weight of the material.

United States Patent James E. ()Connor [72] Inventor South Laguna, Calif. [21] Appl. No. 845,177 [22] Filed July 28, 1969 [45] Patented Oct. 5, 1971 [73] Assignee Document Disintegration, Inc.

Gardena, Calif.

[54] DESTRUCTOR MILLING MECHANISM 2 Claims, 2 Drawing Figs.

[52] U.S.Cl 241/189 R, 241/86, 241/154, 241/285 [51] Int. Cl ..B02c 13/06, B02c 18/14, B02c 18/22 [50] Field ot'Search 241/189 R, 285, 82, 154, 86

[ 56] References Cited UNITED STATES PATENTS 1,763,165 6/1930 Liggett 241/189 R 2,204,069 6/1940 Clement 3,398,901 8/1968 OConnor ABSTRACT: An improved destructor mechanism is described for reducing documents, paper and similar fibrous materials to a fluffy illegible consistency. The mill to be described is equipped with a hood at the entrance to the mill, into which material which is not accepted initially by the mechanism is discharged back through the entrance and circulated, to be reintroduced through the entrance into the mechanism until it is accepted and reduced to the aforesaid fluffy consistency. The mill to be described is particularly advantageous, in that bulky material can be fed into it without the tendency for the apparatus to become jammed, and no special care need be taken in the manner in which the material is fed into the mechanism, or of the size or weight of the material.

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PATENTED 0ST SIB?! SHEET 1 BF 2 BACKGROUND OF THE INVENTION Apparatus for destroying documents, either of a classified nature, or documents which have served their intended purpose, is described, for example, in U.S. Pat. Nos. 3,189,286; 3,192,853 and 3,398,901, all of which have issued in the name of the present inventor.

The mechanism disclosed in the US. Pat. No. 3,398,901, for example, is directly concerned with the problem of adequately destroying documents which are heavy or bulky, such as bound books and papers, and which have a tendency to clog and jam the apparatus. The destruction of such bulky and heavy documents is accomplished in the apparatus of the aforesaid U.S. Pat. No. 3,398,901 by means of a housing providing a pair of interconnecting juxtaposed chambers. In each of the chambers, a power-driven rotor carrying rigidly mounted document-destroying hammers is rotatably mounted, and the rotors are relatively disposed so that the hammers of the two rotors cooperate to produce an implosive effect upon the documents which substantially contributes to the desired end result of the destructive operation.

However, even in the apparatus described in the said U.S. Pat. No. 3,398,901, some care must be taken in the feed of documents and other material into the apparatus, so as to avoid clogging the apparatus with the bulky material.

The teaching of the present invention may be applied to apparatus such as described in the U.S. Pat. No. 3,398,901, and the specific embodiment to be described herein will be considered in such an environment. However, it will become apparent as the description proceeds that the concepts and teachings of the invention have general utility, and may be employed in conjunction with a wide variety of documentdestroying mechanisms.

It has been the practice in the prior art to feed the material into document-destroying mechanisms, such as those described in the aforesaid patents, by directing it into the apparatus from a point displaced above the mechanism. Preferably, the material is fed from a relatively high elevation, so that it may fall and gather momentum as it enters through the top of the apparatus. In the apparatus of the present invention, on the other hand, the material is fed into the entrance of the apparatus along a horizontal chute, for example, or one which is inclined slightly to the horizontal.

The entrance is disposed in the side of a hood which, in accordance with the invention, is mounted over the top of the opening at the top of the mechanism and into the interior of the mechanism. The hood is positioned and configured, so as to provide a circulating chamber for material rejected back through the entrance by the milling mechanism.

In the operation of the apparatus of the invention, for exam- BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side section of a milling mechanism similar to that described in the aforesaid U.S. Pat. No. 3,398,901, and equipped with a hood, to embody the concepts of the present invention; and

FIG. 2 is a view substantially along the line 2-2 of FIG. 1.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENT As shown in the drawings, and as described in greater detail in US. Pat. No. 3,398,901, the mechanism includes a primary mill section and a secondary mill section, designated 14 and 16 respectively in FIG. 1. A primary rotor 18 is mounted on a drive shaft 20 in the primary section, and a secondary rotor 22 is mounted on a drive shaft 24 in the secondary section. The shaft 20, for example, is rotatably supported in a pair of pillow blocks 28 and 30 (FIG. 2); whereas the shaft 24 is rotatably supported in a pair of pillow blocks 32 and 34. The pillow blocks are mounted on an appropriate frame 36.

The secondary section 16 of the mill is disposed at a lower elevation, with respect to the primary section 14, so that the shafts 20 and 24 lie in a plane which is inclined to the horizontal. This inclination may be of the order of 30, for example. It has been found that satisfactory results may be achieved with such an inclination. As explained in the aforesaid patent, although the inclination is not too critical, it has been found that with a 30 inclination, the material is held in the primary section long enough so that it can be reduced to a desired broken-up form before it is introduced into the secondary secpie, as material is fed into the mill through the aforesaid entrance, it falls through the opening into the mechanism and circulates around, in the manner described, for example, in the aforesaid patents. However, any excess material is discharged by the mechanism out through the entrance. This action also occurs in the prior art mechanisms. However, the prior art mechanisms are so constructed that any material rejected by the mechanism itself meets the incoming material, and is directly returned into the mechanism with a tendency to jam and clog the apparatus.

By means of the hood of the present invention, any material rejected by the mechanism is caused to circulate around in the hood, and is not directly in the path of the incoming material. The circulating material may then be fed back into the mechanism, and may continue to circulate in and out of the mechanism itself, until it has arrived at a consistency suitable for acceptance by the mechanism, or, until the incoming load has decreased sufficiently, to permit the mechanism to supply additional material.

tion, and the material introduced into the secondary section enters that section at the optimum angle for maximum explosive effect.

A motor 40 (FIG. 2) drives the shafts 20 and 24 through an appropriate drive mechanism 42. The motor 40, for example, may be a diesel motor, or any other appropriate source of power may be used. The motor 40 drives the shaft 24 through the drive mechanism 42 at the same speed as the shaft 20.

The mill itself is made up of a pair of side plates and 52, which are bolted to the frame 36. The side plates 50 and 52 are mounted in an upright spaced-parallel relationship. The actual primary and secondary sections 14 and 16 of the mill are formed by arcuate-shaped members which extend across from one of the side plates to the other, and which are bolted to the side plates. The side plates 50 and 52, and associated arcuate components define an opening 54 at the top of the primary section 14 through which the material is fed into the primary section of the mill.

The documents and other material which are to be treated in the mechanism are fed through an entrance 57 at the side of hood 56 into the inlet 54 by means, for example, of a chute 55. The chute 55, for example, may be inclined slightly to the horizontal, as shown. The hood 56 is arcuate shaped, as shown, and it is mounted over the opening 54. The hood 56 defines the entrance 57 at its side, through which the material from the chute is caused to enter, to be fed into the mill through the opening 54. A plurality of chains 58 may be suspended across the entrance 57 as a protective means.

An exhaust duct 59 is mounted adjacent an outlet 60 in the housing, and the outlet extends from below the secondary section 16. The pulverized material from the mill is drawn through the exhaust duct 59, and is subsequently disposed of in any suitable manner. The pulverized material may be drawn through the exhaust duct by means of a vacuum pressure, as described in the aforesaid patents.

As shown in FIG. 1, for example, the milling mechanism is actually a dual mill, as described in the aforesaid patent, including the primary section 14 and the secondary section 16. The. secondary section 16 is displaced down from the primary section, as mentioned above, and each operates in conjunction with the other, as described in the patent. That is, neither of the mill sections is suitable for independent operation, and each complements the other, so as properly to perform the desired pulverizing action. A cover 61 forms one of the arcuate components which extends between the side plates 50 and 52. The cover 61 is pivoted to the frame 36 on a shaft 62. A lifter eye 64 is provided at the other end of the arcuate cover 61. The cover is held in place by bolts, such as the bolts 66 extending through a flange of the cover and through the side plates 50 and 52. When the machine is to be opened, these bolts are removed, and the cover may be moved back by a block or a tackle, or by other suitable lifting mechanisms which may be coupled to the eye 64. When the cover is opened, the interior of the secondary section 16 of the mill is revealed.

An arcuate section 68 is bolted to the side plates 50 and 52, and as shown in FIG. 2 this section extends between the side plates adjacent the opening 54 at the top of the section 14. The hood 56 is attached to the arcuate section 68, as best shown in FIG. 1. The inner surface of the section 68 is smooth, so as to define an open area with the primary rotor 18. The material introduced through the side entrance 57 and through the opening 54 into the interior of the primary section 14 is initially exposed to the action of the primary rotor, without any further fracturing action in this open area. In this way, the primary rotor 18 is able to break up the incoming material to some extent as a preliminary measure, so as to minimize the tendency for bulky or heavy material to jam the mechanism.

Moreover, the primary rotor tends to eject the heavy and bulky material back up through the opening 54 and up into the section defined by the hood 56. In this way, the heavy bulky material is recirculated through the primary section and back through the hood 56, and this may occur several times until the bulky material has a composition so as to enable it to be accepted by the mill and further treated without any tendency to jam the mechanism.

A second arcuate section 70 is bolted to the side plates 50 and 52 adjacent the section 68, and this latter section likewise extends from one of the side plates to the other. It will be appreciated that the arcuate sections 68 and 70, and other arcuate sections making up the mechanism, serve to define, with the side plates 50 and 52, the primary section 14 and the secondary section 16 of the mechanism.

A plurality of short breaker bars 72 extend through the arcuate section 70, with the heads of the bars disposed inside the primary section 14 as described in US. Pat. No. 3,398,90l referred to above. These bars are bolted in place, as shown, and are formed, for example, of case hardened steel, with additional hardening being provided for the heads. After the material is fed into the primary section it undergoes a preliminary breaking up action in the open area defined by the arcuate section 68, as mentioned above, and the material is then driven against the heads of the breaker bars 72 by the primary rotor 18, so as to initiate the pulverizing action of the mill. A further arcuate section 76 extends between the side plates 50 and 52 adjacent the arcuate section 70, and in position further to enclose the primary mill section 14. A further group of breaker bars 78 extend through the arcuate section 76, and these breaker bars are held in place by suitable nuts, as shown in FIG. 1.

A further arcuate section 80 is bolted to the side plates 50 and 52, and this latter section extends between the side plates on the opposite side of the inlet 54. A top breaker bar 82 is welded, or otherwise affixed, to the arcuate section 80, and this breaker bar extends between the side plates 50 and 52 to define the upper edge of the opening between the primary section 14 and the secondary section 16. Yet another arcuate section 84 is bolted to the side plates 50 and 52, and extends between the side plates. A bottom breaker bar 86 is welded, or otherwise attached, to the arcuate section 84, and this latter breaker bar forms the lower edge of the opening between the primary and secondary sections 14 and 16 of the mill. The breaker bars 82 and 86 also may be formed of case hardened steel, or other appropriate material.

As mentioned above, the arcuate sections which have been described cooperate with the side plates 50 and 52 to define the primary section 14 of the mill, and the arcuate sections and 84 additionally define a portion of the secondary section 16. The cover 61 also helps to define the secondary section 16, and that section is completed by an arcuate grating 88 which extends between the side plates 50 and 52 at the bottom of the secondary section 16.

The primary rotor 18, as also described in U.S. Pat. No. 3,398,901, includes a plurality of rigid striplike hammer members 90 which are keyed to the shaft 20 by means, for example, of a key 92. The hammer elements 90 are fonned, for example, of case-hardened steel, with additionally reinforced comers. These hammer members 90 are spaced along the shaft 20 and rotate with the shaft. The secondary hammers are indicated 96, and they are keyed to the shaft 25 by means, for example, of a key 98. The secondary hammers, likewise, are rigid and may be formed of case-hardened steel and have additionally hardened edges. As mentioned above, the rotors 18 and 20 are driven in the same direction. Therefore, as the hammers 90 move up in the right-hand portion of the primary section 14, the hammers 96 move down in the left-hand portion of the secondary section 16.

As the material to be destroyed is introduced through the side entrance 57 and down through the opening 54 in the top of the primary section 14, the hammers 90 originally break it up into relatively small pieces in the open area defined by the arcuate section 68 described above. The material is then driven down against the heads of the breaker bars 72 and 78, so that the pulverizing action may begin. Then the material is driven up towards the opening between the primary section 14 and secondary section 16, and against the breaker bars 82 and 86 which define that opening, by the action of the primary rotor 18.

As explained above, part of the material is rejected back through the top opening 54 and up into the chamber formed by the hood 56. The material is then circulated back into the primary section of the mill, and it is ultimately driven up towards the opening between the primary section 14 and the secondary section 16. An implosion area for the material which enters the area between the two sections occurs where the tips of the two sets of hammers 90 and 96 successively pass one another in the opposite direction.

That is, the material fed into the secondary section 16 by the primary hammers 90 is driven directly into the path of the oncoming tips of the secondary hammers 96. Therefore, the tips of the secondary hammers meet the particles of material in midair and contact the particles with a relatively high force. Also, particles from the primary hammers 90 smash at a high force into particles from the oncoming tips of the secondary hammers 96. This implosion of smashing particles against each other creates an additional destruction phase. This action creates a high-speed destruction condition of the material so that it is rapidly reduced to a desired fluffy state. The secondary hammers 96 then carry the fluffy material down against the grating 88, and it is passed through the grating when it reaches a desired illegible flufiy consistency. A further grating 100 is provided, so that the material must be reduced to a particular consistency before it will be passed to the exhaust duct 59. The material to be discharged from the mechanism collects in a chamber 102 under the secondary section 16, and which communicates with the outlet 60. The material may then be withdrawn by appropriate vacuum pressure, as mentioned above, and as described in the aforesaid patent.

An important feature of the mechanism of the present invention is the concept of the hood 56 which permits the material to be fed into the mill through the side entrance 57 by means of the chute 55 from a relatively low position with respect to the floor. This obviates any need to transport the material to a high position relative to the mill and to drip it vertically into the top opening 54. The resulting combination is such that material may be conveniently and easily fed into the mill, and the likelihood of the mill becoming jammed is reduced to minimum, since any excess material is merely rejected back through the top opening 54 and up into the chamber formed by the hood 56 to recirculate in and out of the mill itself, until the necessary conditions are met for the material to be completely processed by the mechanism.

It will be appreciated, of course, that although the mill illustrated in FIG. 1 and 2 herein is shown as a permanent installation, it could just as well be mobile, and could be carried from place to place by means of an appropriate vehicle.

What is claimed is:

l. A milling mechanism for reducing fibrous material, such as documents, paper and the like, into a fiufiy illegible consistency including: a housing defining at least one compartment for the milling mechanism; a rotor including a plurality of hammer elements mounted in said compartment for rotation about a horizontal axis; said housing including components defining a wall for said compartment, said components defining an opening in the wall at the top of said compartment for receiving material into said compartment; and a further component mounted on said housing and extending as a hood around said opening, said hood defining a side entrance for receiving said fibrous material into said milling mechanism and having a generally arcuate configuration so that material discharged from said compartment through said opening is circulated unimpeded around the inner surface of the arcuate wall of a chamber formed by said hood and back into said opening.

2, The combination defined in claim 1, and which includes a chute disposed in a generally horizontal plane and mounted adjacent said side entrance for feeding said fibrous material into the interior of said milling mechanism through said entrance and down through said opening. 

1. A milling mechanism for reducing fibrous material, such as documents, paper and the like, into a fluffy illegible consistency including: a housing defining at least one compartment for the milling mechanism; a rotor including a plurality of hammer elements mounted in said compartment for rotation about a horizontal axis; said housing including components defining a wall for said compartment, said components defining an opening in the wall at the top of said compartment for receiving material into said compartment; and a further component mounted on said housing and extending as a hood around said opening, said hood defining a side entrance for receiving said fibrous material into said milling mechanism and having a generally arcuate configuration so that material discharged from said compartment through said opening is circulated unimpeded around the inner surface of the arcuate wall of a chamber formed by said hood and back into said opening.
 2. The combination defined in claim 1, and which includes a chute disposed in a generally horizontal plane and mounted adjacent said side entrance for feeding said fibrous material into the interior of said milling mechanism through said entrance and down through said opening. 